This website requires certain cookies to work and uses other cookies to help you have the best experience. By visiting this website, certain cookies have already been set, which you may delete and block. By closing this message or continuing to use our site, you agree to the use of cookies. Visit our updated privacy and cookie policy to learn more.

This Website Uses CookiesBy closing this message or continuing to use our site, you agree to our cookie policy. Learn MoreThis website requires certain cookies to work and uses other cookies to help you have the best experience. By visiting this website, certain cookies have already been set, which you may delete and block. By closing this message or continuing to use our site, you agree to the use of cookies. Visit our updated privacy and cookie policy to learn more.

Done digging: Utah district warms up to piping alternative

Faced with leaking underground chiller piping, the Salt Lake City School District needed a solution that would be leak-proof and inexpensive. A polypropylene pipe system ended up meeting those needs.

As
HVAC supervisor for the Salt Lake City School District, Jon Woodward
usually has his hands full. And with 40 years of experience in the
industry, he generally prefers solving problems using proven
technology.

So when he was dealing with
underground leaking chilled water piping at an adult extended
learning center, a new-to-him piping solution was met with
trepidation. Wade Bennion, a principal at Van Boerum & Frank, had
introduced Aquatherm polypropylene piping to Woodward as a solution
after overcoming his own hesitation about using a piping system other
than metal.

Bennion said that in 30 years of
business, he has never been fond of plastic piping. “My father was
the founder of Bennion Associates, and he always said, ‘Every time
you use plastic, you get sued,’ so we stayed away from it,”
Bennion recalled.

Ironically, Aquatherm has
been proven in Europe over the past 30 years. After talking at length
with Aquatherm representatives and with other facility maintenance
professionals who’ve used the product, Bennion realized it was a
perfect fit for this project.

Solution under the horizon

The
Horizonte Instruction and Training Center, an adult extended learning
center located in Salt Lake City, occupies a five-story,
approximately 118,000-sq-ft building that had served as job services
building for 10 years. When the school district bought the building
12 years ago, it completed a mechanical system retrofit, including
new McQuay chillers and 6-in. ductile iron piping (or slip joints)
underground.

Six years ago, one of the slip
joints came apart, causing glycol and chilled water to spew into the
ground. At that point, the plumbers installed new slip joints but
Woodward said they neglected to install new stress blocks, which
later caused problems.

In May 2008, during
maintenance and pressure testing, the district’s facility
maintenance department discovered a leak. The system had failed due
to friction, and the school administration decided to replace only
the bad sections of pipe, amounting to 120 ft.

Initially
Bennion considered replacing the failed pipe with more ductile iron
or CPVC. “They were looking at options, and of course, cost was an
issue. They were looking for fastest, cheapest, permanent solution,
and Aquatherm was the best option,” he said.

Aquatherm’s
Climatherm piping uses heat-fusion to form connections, a process
often used in natural gas piping because of its reliability. Heat
fusion bonds both sides of a joint into a single, homogenous
material, without the use of chemicals or mechanical connections.
This eliminates systematic weaknesses and fail-points in the pipe.
The heat-fusion connection, combined with polypropylene’s
resistance to corrosion and abrasion, eased leakage
concerns.

By June, Bennion had presented
Aquatherm to Woodward as a solid option. “At first, I was a bit
apprehensive about it, but after talking to Wade about the insulating
properties of the pipe and the success it has had in Europe, I said
let’s give it a try,” Woodward said.

The
crew dug up and removed the glycol-contaminated sand surrounding the
pipe and replaced it with 6-in. Climatherm. Since Woodward and his
staff were unfamiliar with the heat fusion process, Aquatherm
dispatched a certified trainer to help the process
along.

“The company was very responsive and
had a trainer onsite. He brought the flanges to connect the ductile
pipe to the piping and showed us how to do the whole thing. He was
very patient and had a lot of knowledge about the product,”
Woodward recalled. In addition to the Climatherm piping retrofit,
stress blocks were added to the remaining ductile pipe.

Left uncovered

After
all the proper testing procedures were followed, Woodward left a
section of the Climatherm and a section of the ductile iron exposed
so he could monitor it into the summer. “We haven’t had any leaks
since the project was finished,” he said, adding that he has been
most impressed with the polypropylene pipe’s insulation
characteristics.

“I couldn’t believe that
there was no condensation on the Aquatherm piping, which was really
surprising since we run 45ºF water through there, and especially
with the heat at that time of year. I am one hundred percent sold on
it, especially for chilled water lines,” Woodward said.

“We
really needed something that would work on this job so I don’t have
to go back in there and do this job again. The product’s
flexibility was a perfect fit for this job.” ES

Engineered Systems magazine’s May 2020 issue examines the revitalization of air-cooled chillers in data center facilities, the viability (or lack thereof) of duct systems, the impact the coronavirus is having on the built environment, and much more.